Bush bearing

Abstract

A bush bearing ( 1 ) is a wrapped bush bearing which has a cylindrical inner peripheral surface ( 2 ) serving as a sliding surface as well as an outer peripheral surface ( 3 ), and whose abutting faces ( 4 ) are abutted against each other. The outer peripheral surface ( 3 ) includes a cylindrical surface ( 11 ); a tapered surface ( 13 ) interposed between the cylindrical surface ( 11 ) and one annular end face ( 12 ) in an axial direction X and formed by roll forming; a smooth circular arc surface ( 14 ) interposed between the tapered surface ( 13 ) and the cylindrical surface ( 11 ); and a smooth circular arc surface ( 15 ) interposed between the tapered surface ( 13 ) and the end face ( 12 ).

1. A combination of a cylindrical wrapped bush bearing and an aluminum-made housing in which the bush bearing is press fitted, said cylindrical bush bearing comprising an inner peripheral surface having a sliding surface, an outer peripheral surface having a cylindrical surface, one annular axial end face, another annular axial end face, and a tapered flat surface interposed and extending continuously in an axial direction from the one annular axial end face toward said other annular axial end face between the cylindrical surface and at least said one annular axial end face and formed by press forming, wherein a difference δ (=r 1 −r 2 ) between a radius r 1  of the cylindrical surface of the outer peripheral surface and a radius r 2  of an outer peripheral edge of the one annular axial end face is in a range of not less than 0.1 t and not more than 0.3 t, where t is a wall thickness of the bush bearing at the cylindrical surface of the outer peripheral surface, wherein, the bush bearing including a multilayered plate which has the sliding surface on one surface thereof and is convoluted into a cylindrical shape such that the sliding surface is positioned on an inner peripheral side, said multilayered plate including a back plate entirely coated with copper, a porous sintered metal layer adhered integrally to a copper coating layer on one surface of the back plate, and a sliding layer including a synthetic resin with which the porous sintered metal layer is impregnated, and which has self-lubricity and wear resistance, a portion of said sliding layer being formed on one surface of the porous sintered metal layer, the cylindrical surface, the tapered surface and the one annular end face consisting of an exposed surface of the copper coating layer, said bush bearing further comprising a first smooth circular arc surface interposed between the tapered surface and the cylindrical surface, the first smooth circular arc surface having a radius of curvature which is not less than 0.1 mm and not more than 1.0 mm, and a second smooth circular arc surface interposed between the tapered surface and the one annular axial end face, the second smooth circular arc surface having a radius of curvature which is not less than 0.1 mm and not more than 0.5 mm, an angle θ of intersection between the tapered surface and an axial line being not less than 15° and not more than 25°, the outer peripheral edge of the one annular axial end face having a smaller diameter than a diameter of a hole of the aluminum-made housing in which the bush bearing is press fitted. 
     
     
       2. The combination according to  claim 1 , wherein the tapered surface is formed by roll forming. 
     
     
       3. The combination according to  claim 1 , wherein the outer peripheral surface of the bush bearing further has, in addition to the tapered surface interposed between the cylindrical surface and the one annular end face, another tapered surface interposed between the cylindrical surface and the other annular axial end face of the bush bearing and formed by press forming. 
     
     
       4. The combination according to  claim 3 , wherein the other tapered surface extends in the axial direction continuously from the other annular end face, and the cylindrical surface extends continuously in the axial direction from the other tapered surface toward the one axial end face of the bush bearing. 
     
     
       5. The combination according to  claim 3 , wherein the other tapered surface extends in the axial direction between the cylindrical surface and the other annular end face so as to be flat or convex toward the outside. 
     
     
       6. The combination according to  claim 3 , wherein a smooth circular arc surface is interposed between the other tapered surface and the cylindrical surface. 
     
     
       7. The combination according to  claim 6 , wherein the smooth circular arc surface interposed between the other tapered surface and the cylindrical surface has a radius of curvature which is not less than 0.1 mm and not more than 1.0 mm. 
     
     
       8. The combination according to  claim 3 , wherein a smooth circular arc surface is interposed between the other tapered surface and the other annular end face. 
     
     
       9. The combination according to  claim 8 , wherein the smooth circular arc surface interposed between the other tapered surface and the other annular end face has a radius of curvature which is not less than 0.1 mm and not more than 0.5 mm. 
     
     
       10. The combination according to  claim 3 , wherein an angle of intersection, θ, between the other tapered surface and the axial line is not less than 15° and not more than 25°. 
     
     
       11. The combination according to  claim 3 , wherein the other tapered surface is formed by roll forming. 
     
     
       12. The combination according to  claim 3 , wherein the other tapered surface is constituted by an exposed surface of the copper coating layer.